Crop growers frequently apply herbicides, pesticides, and/or plant growth regulators (“active ingredients”) in order to achieve healthier plants. The active ingredients are often mixed in a tank at or near the field and applied to the crop growing area shortly thereafter. In order to be as efficient as possible, it is desirable to apply as many of the active ingredients as possible at one time in order to minimize labor and equipment transportation costs.
Unfortunately, crop growers have been limited to certain active ingredients that can be applied simultaneously due to the physical incompatibility of many of the active ingredients. For example, many active ingredients, if mixed in a tank with water, would cause the tank mixture to separate into layers. Other combinations of active ingredients would react and form a precipitate that would fall to the bottom of the tank. Another example of incompatibility is that some combinations form a gel in the tank and therefore cannot be dispensed. In all of these examples, it is difficult to provide the crop growing area with an even distribution of the active ingredients. Uneven distribution could lead to phytotoxicity or low efficiency of the actives/waste of resources.
Dicamba diglycol amine (diglycolamine salt of 3,6-dichloro-o-anisic acid) is an herbicide that is very effective for the management of broadleaf weeds, brush and vines.
Lactofen (ethyl O-[5-(2-chloro-α,α,α-trifluoro-p-tolyloxy)-2-nitrobenzoyl]-DL-lactate) is a complex ester of acifluorfen and is a nitrophenyl ether selective herbicide. Lactofen is very effective as a post emergent weed controller.
It is desired by crop growers to apply dicamba diglycol amine and lactofen in a tank mix, however, due to their physical differences this has not been successful. Dicamba diglycol amine is water-soluble but lactofen is a solid with a low melting point and is not water-soluble. Mixing a water-soluble active ingredient with a water-insoluble active ingredient usually leads to precipitation, gelling or phase separation. Given the complexity of formulation science, it is difficult to determine which adjuvants (if any) would provide a stable formulation.
US Patent Application Publication No. 2012/0142532 is directed to stabilized herbicide solutions which contain dicamba mono ethanol amine. However, this publication fails to teach a formulation containing the more active salt, dicamba diglycol amine. Further, this publication fails to teach one of skill in the art how to produce a stable formulation which includes lactofen and dicamba diglycol amine.
US Patent Application Publication No. 2014/0080706 is broadly directed to a method of controlling undesired vegetation by preparing a tank mix having a pH of at least 7 comprising a pesticide formulation (which may include dicamba), water, a base and, optionally, an auxiliary wherein the base contains a carbonate and/or a phosphate and has a solubility in water of at least 1 g/l at 20 degrees C. This publication, however, fails to teach stable liquid premixture formulations with a pH of less than 7.
Accordingly, there is a need in the art for stable liquid premixture formulations that can include lactofen and dicamba diglycol amine. The formulations should be shelf stable and should also be able to be diluted in a tank mixer prior to application to a plant growing area.